2025 Mercedes-Benz Metris — A/C Refrigerant & Oil Specs

Quick answer

• Refrigerant: R-1234yf (most late W447/Metris vans use R-1234yf; always confirm on the under‑hood label)
• Full system charge: Typically ~650–750 g (23–26 oz) for front A/C only; ~900–1100 g (32–39 oz) if equipped with rear A/C. Exact fill varies by build/options—verify the under‑hood label for the precise gram/oz value.
• PAG oil: PAG 46 (ND‑12 equivalent for R‑1234yf). Total system oil commonly ~120–150 mL (4.0–5.1 oz). Component replacement oil amounts vary—follow WIS/ASRA.
• Service ports:
  • Low side: On the larger‑diameter suction line, typically along the right/passenger side of the engine bay near the firewall/accumulator area.
  • High side: On the smaller‑diameter liquid line near the condenser at the front (behind grille, left/front side on many vans). Trace lines to confirm.

Note: Do not rely on pressure to determine charge. Use the exact charge by weight listed on the Metris under‑hood A/C label (radiator support or underside of hood). Trims/options (rear A/C, auxiliary heater, different condensers) change the spec.

Why R-1234yf matters

• Compliance and environment: R‑1234yf is the mandated low‑GWP replacement for R‑134a in most late‑model vehicles. Using the wrong refrigerant or mixing types can damage components and is an EPA violation.
• Cost: YF is significantly more expensive than R‑134a, and it’s sold in smaller containers. Accurate evacuation and charge by weight are essential to avoid wasted refrigerant and poor performance.
• Equipment: R‑1234yf requires dedicated recovery/recycle/recharge machines (SAE J2843) and YF‑specific fittings. R‑134a tools and machines are not compatible.
• Safety: R‑1234yf is mildly flammable (A2L). Follow OEM procedures, keep ignition sources away, and ensure good ventilation.

Recharge procedure (high‑level)

1. Identify the exact specification: Read the under‑hood A/C label for refrigerant type, capacity (grams/ounces), and oil information. Cross‑check in Mercedes‑Benz WIS/ASRA.
2. Inspect and leak test: Visually inspect lines, condenser, compressor, and fittings. If the system is empty, find and fix leaks before charging. Do not add “stop‑leak” products—they contaminate equipment and can damage components.
3. Recover any remaining refrigerant: Use an SAE‑approved machine to properly recover R‑1234yf.
4. Evacuate: Pull vacuum to ~29 in‑Hg for at least 20–30 minutes, then close valves and verify the system holds vacuum (no decay) for 5–10 minutes. Vacuum integrity matters more than time alone.
5. Charge by weight: Charge the exact amount listed on the vehicle label using a calibrated scale. Do not charge by pressure or can count.
6. Oil management: If components were replaced, add the correct amount of PAG 46 (ND‑12) per WIS/ASRA. Distribute oil when possible (e.g., split between components per OEM guidance). Replace the receiver‑drier any time the system is open to atmosphere or after compressor failure.
7. Post‑charge checks: With A/C on MAX and doors open, verify clutchless variable compressor command, condenser fan operation, and vent temps. Compare high/low pressures to typical YF performance charts, but remember pressure is not a fill indicator.

Common A/C problems for this vehicle

• Condenser damage/leaks: The Metris/Vito (W447) condenser sits low and forward, susceptible to road debris and rock impacts leading to slow leaks.
• Compressor control valve or compressor wear: Variable‑displacement compressors can lose capacity due to a sticking control valve or internal wear, causing warm air at idle or under load.
• Refrigerant leaks at crimp joints and service ports: O‑rings and hose crimps can seep over time; service port cores may leak after prior service.
• Evaporator core leaks: Less common but possible; sweet odor or oily residue at the case drain. UV dye or electronic sniffers help confirm.
• Rear A/C (if equipped): Long lines and rear evap/connections underbody can corrode or chafe, especially in salted climates.
• HVAC door actuators and temp sensor faults: Blend/air‑mix actuator issues can mimic low charge. Scan for HVAC codes and read sensor data before replacing parts.

OEM service information

• Always verify specifications on the under‑hood label and in Mercedes‑Benz WIS/ASRA for your exact VIN and option codes (e.g., with/without rear A/C).
• Use MB‑approved PAG oil equivalent to ND‑12 for R‑1234yf systems, and replace the receiver‑drier per WIS any time the system is opened.
• Observe all WIS procedures for evacuation, charging, leak testing (nitrogen plus trace gas), and component torque specs.

When to call a pro

• You don’t have an R‑1234yf machine or scale to charge by weight.
• The system won’t hold vacuum, or leak detection points to an evaporator or rear A/C line (dash/interior or underbody work required).
• After a compressor failure (black death/metallic debris): the system needs thorough flushing, a new drier, orifice/expansion device, and sometimes a condenser.

Safety disclaimer: Servicing mobile A/C with regulated refrigerants requires EPA Section 609 certification in the U.S. Use only the refrigerant specified on the vehicle label. Never vent refrigerant. Follow all OSHA/fire safety practices when working with R‑1234yf (A2L).

Find a certified A/C shop on Repairius.